[Samson68]

What’s up guys aside from air fuel ratio gauge selection I got in another post I’m trying to dial in my suspension for maximum traction and function. I installed promastar qa1 coilovers dual adjustable in the rear 130 springs st me rear ride height where my 33x 21.5 street radials would clear my tubs. Center to center is 16 1/4 w weight on car. .... I have two holes in my front hiem joints for my ladders it’s currently on the lower hole and my digital degree finder says it’s 1.7 degrees lower in the front. I’m not gunna raise the rear any further as I’m under the impression lower is better hopefully someone will agree or correct me on that. Now I’m moving to my front it has stock a arms and coil springs in stock location. I know it needs to be up graded I was thinking I need to raise the front end a few inches putting my big block higher in the chassis for better weight distribution as well as maybe upgrade to either moroso coils w lighter weight rating or maybe go adjustable qa1 coilover s the car will get faster in the upcoming years and I wanna be able to continue adjusting my ladder and front end to meet the best possible launch. If I raise my front end up my bottom hole in my ladder bar to about .5 degrees do I want my lower hole as close to parallel as possible?? I can make it lower the faster I get. What do u guys think

 

[Samson68]

I’m not gunna mess w my pinion angle till I get my ride height correct cuz it’s mute at this point but would like a short explanation about it all getting dialed in I do have the dock Miller book I’ve been reading the crap out of it

 

[Samson68]

Bump?

 

[chevcraz]

Hello
Drag race only car?
Back half aftermarket rear suspension?
When the car was built it has the basic weight locations & intersect points engineered into it.
If so, my experience tells me you will need to do measurements on the chassis to determine the set up.
Find some wheel scales, scale the car and determine the CG.
Set the suspension based on those measurements and test.
The engine power will also come into play, more torque will require less pitch rotation (weight transfer).
By lowering your front ladder bar point you are moving the intersect point further forward, depending where the CG is this will change the pressure on the rear tire and the forces applied to the chassis, to the good or bad. To say if this will help is impossible until you test it or know the CG & dimensions. It will save a bunch of time, and you can make accurate decisions if you know the dimensions.
I made a mistake with my car, making the car look cool by making it low. This actually hurt my chassis rotation as I did not have loads of torque.
If you like to read Door slammers by Dave Morgan is a great book to figure it out. I saved me loads of time and made my car way more consistent.
Work with the math, you can't work against it.
Hope it helps

Edit;
Should also ask what was the car doing now that you are trying to correct?

 

[Samson68]

Thanks for the reply bro I haven’t weighed he car yet I got a local trucker place that can give me front and rear but not all 4 corners I felt like getting adjustable coilover s in the front instead of those obviously altered front springs will help me assist in gaining that sweet spot. I do need to find center of gravity it’s an iron headed bbc the way u explained it made total sense ahh back to the drawing board I’m only pushing about 525 to 550 ft pounds I’m feeling like if my calculations are correct I need every ft on the ground I can get

 

[Samson68]

Hello
Drag race only car?
Back half aftermarket rear suspension?
When the car was built it has the basic weight locations & intersect points engineered into it.
If so, my experience tells me you will need to do measurements on the chassis to determine the set up.
Find some wheel scales, scale the car and determine the CG.
Set the suspension based on those measurements and test.
The engine power will also come into play, more torque will require less pitch rotation (weight transfer).
By lowering your front ladder bar point you are moving the intersect point further forward, depending where the CG is this will change the pressure on the rear tire and the forces applied to the chassis, to the good or bad. To say if this will help is impossible until you test it or know the CG & dimensions. It will save a bunch of time, and you can make accurate decisions if you know the dimensions.
I made a mistake with my car, making the car look cool by making it low. This actually hurt my chassis rotation as I did not have loads of torque.
If you like to read Door slammers by Dave Morgan is a great book to figure it out. I saved me loads of time and made my car way more consistent.
Work with the math, you can't work against it.
Hope it helps
View attachment 703886
Edit;
Should also ask what was the car doing now that you are trying to correct?

The car is feeling a bit nose heavy as I expected I can feel the front end moving slightly but nowhere near enough since I got those massive tires which I’m starting to dislike bye lol I’m stuck keeping the rear end at a certain height or higher w my qa1s I can raid the rear another 1.25 inches but not down and I really dnt want to go higher as Itl throw my extension shorter and pull my lower hole in the ladders to positive at that point. If I raise the front up I can gain 1 degree and remain almost flat on the lower hole and still move up one to a few degrees positive for more tuning later. I realize that all this is irrelevant till I get c of g but I’m kinda stuck w working where my rear tires are at

 

[chevcraz]

Yes raising the front will move the CG back. Since you’re restricted in the back end, and you want to modify the front, try to have as much adjustments as possible. Scales save time but track test and tune works. Cutting weight off the front would help too.
If you can get the F&R weight that would be good.

 

[Samson68]

Yes raising the front will move the CG back. Since you’re restricted in the back end, and you want to modify the front, try to have as much adjustments as possible. Scales save time but track test and tune works. Cutting weight off the front would help too.
If you can get the F&R weight that would be good.

Ok hmm it’s Friday I’m off might be the day to see if I can get it weighed I’ll let you know what I find out

 

[bracketchev1221]

I would leave the front of the bar where it is now. Don't forget to figure it with your weight in the seat.

 

[Samson68]

I would leave the front of the bar where it is now. Don't forget to figure it with your weight in the seat.

Yessir will do

 

[Samson68]

Ok weighed front I’m 2000 pounds even rear I’m 1740 both weights are w me sitting in it and ohh maybe about a 1/4 to 1/2 a tank of fuel. What math equations do I need to apply at this point

 

[chevcraz]

You were quick haha.
The weights can be used to calculate F&R weight splits, C/L location in your wheel base (your CG is hiding above the C/L), where your front ladder bar point is in relation to your C/L and what springs to get.
You said the car does not get the front end moving enough with the big rear tire, how was it before the new tires?
If there was a big change in tire diameter could you be looking at a gear ratio change as well?
Using a lighter rate spring with more shock travel will help you with getting the front end up with less force, engine torque can then be better applied to the chassis and rear tire. Moving some mass rearward will help too.
I don't mean to geek out so much on the math, but that's what really helped me be wise with chassis decisions, faster car, not spending as much on parts haha. I don't want to plagiarize the book from Dave Morgan.
Getting back to your original questions;

• For the pinion angle I would start at 1 to 2 degrees down static. Adding more angle will slow the movement of the axle housing.
• Leave the bars where they are.
• The front weight is above the ratings of the Moroso springs, so you may have to move some weight to get desired static ride height.
• Use some adjustable front shocks to match the rears, or go with C/O like you said. One thing I got burned by was C/O with too short a travel. Longer is better IMO, you can always restrict it if you need to.
• Have some sturdy bump stops so your chassis takes the load not the shock
• Test & tune

Hope this helps
Cheers 🍻 Its beer time haha.

 

[Samson68]

Dude your awesome much needed info not that fast I’ve been talking to this trucking company for a month about coming over Haa I believe my nose isn’t moving as much due to the suspension and the shocks and the low front I got the car w these tires I don’t know the width of the rim but would love to go smaller currently it has 4.11s on a 33 not great for all out but in 3rd w my th350 I’m cruising 40 ish at 2200 rpm it does snack 6 k very quickly I’d hafta find the formula for final gear w that big of a tire (33x21.5 ) my pinion is currently set at about 2 degrees ( that’s driveline and pumpkin added together) I think imma do front uppers n lowers and new coilover s and raise the nose till my bar hits 0 degrees that’s 2.5 inches according to my torpedo digital. Loosen up the rebound grab bump stops like u said and see what happens from there. How do I find my c/l mathematically and my percentage of weight ratio? What’s the formula and I could swap gears ( I have a dana 60) what do u think? My plans for the motor is a procharger in a few years I gotta think ahead as well as right now 😝 go figure..... that’s hot rodding lol

 

[chevcraz]

Glad its the info your looking for
For the uppers and lowers look for poly bushings or similar using grease if you have the stock arms, you want free range of motion for the entire travel. Rubber will lock up at ride height and not give you full free range.
C/L dimension, this is the basic math;

• Find the weight % on each axle. (Front end weight / Total weight) x 100 = Front weight %.
• 2000 / 3740 = .535 or 53.5%
• You can convert the axle weight % into wheel base dimension. % Weight front = % Distance rear tire to car C/L. Or % Weight rear = % Distance front tire to car C/L. So Wheel base x axle weight split = distance
• So if you have 112" wheel base the rear distance in this example would be 112" x .535 = 59.92"

Gear ratios are tricky. The engine powerband, torque converter all come into play. 60' times and trap speed need to be balanced. I looked for a few hundred RPM over shift point through the traps, but there is a lot to that figuring. Wallace Racing has all sorts of calculators
Wallace Racing - Automotive Calculators

 

[Samson68]

Glad its the info your looking for
For the uppers and lowers look for poly bushings or similar using grease if you have the stock arms, you want free range of motion for the entire travel. Rubber will lock up at ride height and not give you full free range.
C/L dimension, this is the basic math;

• Find the weight % on each axle. (Front end weight / Total weight) x 100 = Front weight %.
• 2000 / 3740 = .535 or 53.5%
• You can convert the axle weight % into wheel base dimension. % Weight front = % Distance rear tire to car C/L. Or % Weight rear = % Distance front tire to car C/L. So Wheel base x axle weight split = distance
• So if you have 112" wheel base the rear distance in this example would be 112" x .535 = 59.92"

Gear ratios are tricky. The engine powerband, torque converter all come into play. 60' times and trap speed need to be balanced. I looked for a few hundred RPM over shift point through the traps, but there is a lot to that figuring. Wallace Racing has all sorts of calculators
Wallace Racing - Automotive Calculators

Ok cool I’ll get to some figuring and let you know what I come up with. My stall speed w foot on the brake when it flashes is around 22 to 2500 rpm if I were to mess w rear is most likely just start getting smaller tires rather than gear sets lol I love the variety of variables at play here as I’m def a ponderer and this is partly a thinking mans game. Most curious and hungry for learning about this stuff. Thank you for the information you’ve been a great help I’m sure I’ll be hitting u up for more lol

 

[Kirk's67SS]

So are you saying you only have a 2200 to 2500 Stall Converter ?

You do not necessary have to increase/Raise the Height of the Front End of the Car to get Weight Transfer for Traction at Launch

If you go with Front Coil Overs you have to get the Top Extenders so they will work Better/Properly

Here is a Pic of my Car Car when it ran in the Low 13s Hi 12s in the 1/4
with 3.55 Rear Gears and Stock Coil Springs & Shocks and a 2500 Stall Converter / 275/60/15 Rear Street Tires

Here is a Pic of my Car Car when it ran in the Hi to Mid 12s in the 1/4
with 3.70 Rear Gears and Viking DA Shocks Front Coil Overs & 2500 Stall Converter / 275/50/15 Rear Street Tires

Here is a Pic of my Car Car when it ran in the Low 12s to Hi 11s in the 1/4
with 3.70 Rear Gears Moroso Trick Springs/Comp Eng 3 WayShocks/2500 Stall Converter/275/50/15 R Street Tires

Here is a Pic of my Car Car when it ran in the Hi 11s to Mid 11s in the 1/4
3.70 Rear Gears/Moroso Trick Springs/Comp Eng 3 WayShocks/3500+ Stall Converter/295/55/15 R Street Tires

See my Sig for ET Times

 

[Samson68]

So are you saying you only have a 2200 to 2500 Stall Converter ?

You do not necessary have to increase/Raise the Height of the Front End of the Car to get Weight Transfer for Traction at Launch

If you go with Front Coil Overs you have to get the Top Extenders so they will work Better/Properly

Here is a Pic of my Car Car when it ran in the Low 13s Hi 12s in the 1/4
with 3.55 Rear Gears and Stock Coil Springs & Shocks and a 2500 Stall Converter / 275/60/15 Rear Street Tires
View attachment 704338

Here is a Pic of my Car Car when it ran in the Hi to Mid 12s in the 1/4
with 3.70 Rear Gears and Viking DA Shocks Front Coil Overs & 2500 Stall Converter / 275/50/15 Rear Street Tires
View attachment 704339

Here is a Pic of my Car Car when it ran in the Low 12s to Hi 11s in the 1/4
with 3.70 Rear Gears Moroso Trick Springs/Comp Eng 3 WayShocks/2500 Stall Converter/275/50/15 R Street Tires
View attachment 704340
View attachment 704342

Here is a Pic of my Car Car when it ran in the Hi 11s to Mid 11s in the 1/4
3.70 Rear Gears/Moroso Trick Springs/Comp Eng 3 WayShocks/3500+ Stall Converter/295/55/15 R Street Tires
View attachment 704341
View attachment 704345

See my Sig for ET Times

I’m pretty sure I will be going w coil overs for future adjustments needed when I start adding power. I dont wanna buy stuff twice either even in all your pics ur front end is a lot higher than mine I have a 8 quart hamburger pan and I got an inch of ground clearance lol she’s gotta come up and my suspension is way too tight up front. Imma leave it for a sec till my money tree blooms again and get after it top extenders?

 

[Kirk's67SS]

I’m pretty sure I will be going w coil overs for future adjustments needed when I start adding power. I dont wanna buy stuff twice either even in all your pics ur front end is a lot higher than mine I have a 8 quart hamburger pan and I got an inch of ground clearance lol she’s gotta come up and my suspension is way too tight up front. Imma leave it for a sec till my money tree blooms again and get after it top extenders?

Okay
I guess if I would have seen a Pic of your Car's Stance then I would have seen that it is/was very Low in Front

 

[Samson68]

Okay
I guess if I would have seen a Pic of your Car's Stance then I would have seen that it is/was very Low in Front

Your cars sweet bro! what are top extensions? I’m prolly gunna be like ohh those yes haahaa

 

[Samson68]